JP2526194B2 - Hybrid IC - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid IC in which an electronic component element on a substrate is sealed with a protective layer made of an insulating resin and a shield layer is formed thereon.

[0002]

2. Description of the Related Art A hybrid IC is used by mounting it on a printed wiring board, and its electronic component element is covered with a protective layer of an insulating resin to protect it from the external environment. A shield layer is formed to block the external influence of the electromagnetic wave emitted from the hybrid IC and the external influence on the hybrid IC.

To form the shield layer, there are means for providing an outer case of a metal case and means for applying a conductive substance as disclosed in Japanese Utility Model Laid-Open No. 61-75192. The former has a large shape and is expensive. On the other hand, the latter has the advantages that the entire hybrid IC can be downsized and the manufacturing cost is low.

However, a conductive paint is usually used as the above-mentioned conductive substance, but conventionally, a paint which has a viscosity suitable for coating and a sufficient conductivity and which can sufficiently obtain a shielding effect is proposed. The reality is that it has not been done. There is nothing satisfactory that can be used for dip coating, which has particularly good workability.

In view of the above situation, it is an object of the present invention to make the shield layer dip-coatable and have sufficient conductivity.

[0006]

In order to solve the above-mentioned problems, according to the present invention, an electronic component element is mounted on a substrate, and a protective layer of an insulating resin is formed on the electronic component element. A number of lead terminals are protruded from the protective layer, and a shield layer of conductive paint having the following composition (A) to (D) is formed on the protective layer, and the shield layer is a ground lead terminal among the lead terminals. In the well-known hybrid IC electrically connected only to the above, the shield layer is made of a conductive coating material having the composition of (A) to (D) below.

Note (A) 100 parts by weight of metallic copper powder surface-coated with 0.05 to 0.2 parts by weight of titanate, zirconate, or a mixture thereof (B) 5 to 33 parts by weight of resol type phenolic resin (C) Amino compound 0.5 to 3.5 parts by weight (D) Chelate layer forming agent 3.0 to 10 parts by weight.

The above-mentioned conductive paint can be blended with the following (A) to (E). Note (A) 100 parts by weight of metallic copper powder surface-coated with 0.05 to 0.2 parts by weight of titanate, zirconate, or a mixture thereof (B) 5 to 30 parts by weight of resol type phenolic resin (C) thixotropic adjustment Material 0.5 to 4 parts by weight (D) Amino compound 0.5 to 3.5 parts by weight (E) Chelate layer forming material 3.0 to 10 parts by weight.

The above-mentioned resol type phenol resin is preferably the following. The 2-1 substitution product, 2,4-2 substitution product, 2,4,6-3 substitution product, methylol group, dimethylene ether, each infrared transmittance of phenyl group is 1, m, n, a, b, When c,
Between each transmittance, (a) l / n = 0.8 to 1.2 (b) m / n = 0.8 to 1.2 (c) b / a = 0.8 to 1.2 ( D) A resole type phenolic resin in which the relationship of c / a = 1.2 to 1.5 is established.

The protective layer and the shield layer may be formed by dip coating in which the substrate on which the electronic component element is mounted is sequentially dipped in an insulating resin bath and a conductive paint bath.

The substrate material is an insulating material such as epoxy resin, phenol resin, glass fiber or ceramics.

The metallic copper powder may have any shape such as flakes, dendritic shapes, spherical shapes, and irregular shapes. Particle size is 10
It is preferably 0 μm or less, and particularly preferably 1 to 30 μm.
Particles having a particle size of less than 1 μm are easily oxidized and the conductivity of the resulting coating film (coating film) is lowered, which is not preferable.

The metallic copper powder is titanate, zirconate, or a mixture thereof (hereinafter referred to as dispersibility-imparting agent).
The surface coating of the resin promotes fine dispersion in the resin mixture, thereby stabilizing the quality of the conductive paint and improving the conductivity. The amount of the dispersibility-imparting agent added is 0.05 to 0.2 with respect to 100 parts by weight of the metal copper powder.
Parts by weight. When the added amount of the dispersibility-imparting agent is less than 0.05 parts by weight, the conductivity of the coating film is reduced, and when it exceeds 0.2 parts by weight, the adhesion to the copper foil (copper alloy foil) and the solder Heat resistance is not preferable. The dispersibility-imparting agent may be added alone, or the solvent may be removed after being added as a solution. Incidentally, this surface treatment makes it unnecessary to add a dispersant.

When the content of the resol-type phenol resin is less than 5 parts by weight, the metallic copper powder is not sufficiently bound and the resulting coating film becomes brittle. Further, if the amount exceeds 33 parts by weight, and if the amount exceeds 30 parts by weight in the case of adding the thixotropic adjusting agent, the conductivity will decrease. It is preferably 9 to 20 parts by weight.

Further, the stoichiometry, the amount of the 2-1 substitution product is λ,
The amount of 2,4-2 substitution product is μ, the amount of 2,4,6-3 substitution product is ν, the amount of methylol group is α, the amount of dimethylene ether is β,
When the amount of phenyl group is γ, 1 / n and m / n of the above-mentioned constitution
Is large, it means that λ / ν and μ / ν are small. That is, the amount of 2-1 substitution product λ, 2,4-2
This means that the amount of 2,4,6-3 substitution product ν is larger than the substitution product amount μ. In addition, b / a, c /
A large a means that β / α and λ / α are small. That is, it means that the amount of methylol groups α is larger than the amount of dimethylene ether β and the amount of phenyl groups λ.

Generally, when the 2,4,6-3 substitution product amount ν increases, the crosslink density of the resol-type phenol resin also increases, so that the smaller λ / ν and μ / ν, that is, 1 / n. , M / n is larger, the conductivity of the coating film is better. However, on the contrary, the coating film tends to be hard and brittle, and the physical properties deteriorate. If β / α is small, the solderability of the coating film is poor, and if γ / α is large, the conductivity of the coating film is poor.

Therefore, in the obtained conductive coating material, the resol type phenolic resin having suitable hardness of the coating film and having good conductivity and solderability is the l / n, m / n shown in the above-mentioned constitution. , B / a are 0.8 to 1.2, and c, respectively.
It is suitable that / a is 1.2 to 1.5.

The chelate layer forming agent is at least one selected from aliphatic amines such as monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, triethylenediamine and triethylenetetramine.
It is a seed. The chelate layer forming agent prevents oxidation of the metal copper powder and contributes to maintaining conductivity. The blending amount is 3.0 to 10 parts by weight with respect to 100 parts by weight of the metal copper powder. If the blending amount is less than 3.0 parts by weight, the conductivity of the coating film decreases, and conversely, if it exceeds 10 parts by weight, the conductivity of the coating film also decreases.

The thixotropic modifier is intended to eliminate sagging during coating. The adjusting agent is at least one selected from polyvinyl butyral resin, polyvinyl formal resin, acrylic resin, paravinylphenol resin and the like. The blending amount of this regulator is 0.5 with respect to 100 parts by weight of metallic copper powder.
~ 4 parts by weight. When the amount of this adjusting agent is less than 0.5 parts by weight, the sagging cannot be improved, and when it exceeds 4 parts by weight, the conductivity of the coating film is remarkably lowered.

The amino compound acts as a reducing agent in addition to the conductivity enhancer, prevents oxidation of the copper metal powder, and contributes to maintenance of conductivity. The blending amount is 0.5 to 3.5 parts by weight with respect to 100 parts by weight of the metal copper powder. If the blending amount is less than 0.5 parts by weight, the conductivity of the coating film is remarkably lowered, and conversely 3.5.
When it exceeds the weight part, the conductivity is saturated and no further improvement is observed.

Specific examples of the amino compound include aniline, diphenylamine, phenylenediamine, diaminonaphthalene, anisidine, aminophenol, diaminophenol, acetylaminophenol, aminobenzoic acid, N, N-diphenylbenzidine and the like, or There are several types, but the present invention is not limited thereto.

For the conductive paint, a usual organic solvent can be appropriately used in order to adjust the viscosity. For example, known solvents such as cellosolve acetate, carbitol, butyl carbitol, and butyl cellosolve acetate.

[0023]

As can be understood from the above description, the conductive coating material according to the present invention having such a structure has excellent conductivity and adhesiveness of the coating film, and has high conductivity even when the viscosity is low. is there. Therefore, like the protective layer, the shield layer can be easily formed by dip coating on the conductive paint bath.

[0024]

EXAMPLE First, 100 parts by weight of a dendritic metal copper powder having a particle size of 5 to 10 μm and a specific surface area of 0.4 m ² / g or less and a hydrogen reduction weight loss of 0.25% or less was put into a stirrer to prepare a titanate. Was added little by little and stirred to coat the surface of the metal copper powder with titanate. After that, the copper metal powder was mixed with aminophenol as a reducing agent, triethanolamine as a chelate layer forming agent, a resol type phenol resin having an infrared transmittance ratio shown in Table 1, and a polyvinyl butyral resin (BM- 1, manufactured by Sekisui Chemical Co., Ltd., respectively, in the proportions shown in Table 1, and used as a solvent.
A mixed solvent of ethyl carbitol and butyl cellosolve was added, and the mixture was kneaded in place with a triaxial roll for 20 minutes, and the viscosity was adjusted to 20 to 40 P using a measuring machine VT-04 manufactured by Rion Co., Ltd. to obtain a conductive paint bath.

In place of ethyl carbitol or butyl cellosolve, known ones such as butyl carbitol, butyl carbitol acetate, butyl cellosolve acetate, methyl isobutyl ketone, toluene and xylene can be used.

[0026]

[Table 1]

[0027]

[Table 2]

On the other hand, as shown in FIG. 1, electronic component elements such as various chip components 2 and resistors 3 are mounted or printed on the epoxy resin substrate 1 and the required number of lead terminals 4 ... ... 4a is projected.

The substrate 1 is masked at the base portion 4a 'of the ground lead terminal 4a and immersed in an epoxy resin bath to form a protective layer 5 having a required thickness. At the time of the immersion, the ground lead terminals 4a are soaked up to the exposed portion (connection portion), that is, the connection portion is left so that the other lead terminals 4 ... Are reliably filled and covered with resin. This is to prevent short-circuiting between the shield layer 6 and the lead terminal 4 described later.

Subsequently, the substrate 1 is dipped in the conductive paint bath with the masking removed to form a shield layer 6 having a required thickness. The immersion depth should not reach the edge of the protective layer 5 on the side of the lead terminals 4 and 4a. By this immersion, the conductive paint enters the masking portion 4a ', and the ground lead terminal 4a and the shield layer 6 are electrically connected.

The superiority of the hybrid IC of this embodiment can be understood by the following test.

That is, as shown in FIG. 2, each conductive paint b shown in Table 1 was applied to a through hole 33 (hole diameter 0.8 mm) of a paper phenol substrate 32 having a thickness of 1.6 mm by using a 80 mesh Tetoron screen. Embedded by screen printing. Then, after drying at 25 ° C. ± 5 ° C. for 24 hours, it was heated at 160 ° C. for 30 minutes using an air oven to cure the coating film.

As shown in FIG. 3, the through hole 33 has 20 holes forming a row in the lateral direction, and a large number of such rows A to K are provided. On the front side of the substrate 32, two adjacent through holes 33, 33 ... Are connected by a copper foil 34 (see a in the figure), and on the front side two through holes are not connected by the copper foil 34. 33, 33 ... are copper foils 34 ', 3 on the back side.
4 '(see b).

Ends 41 to 42, 42 to 43, 43 to 44
The series resistance value of 20 holes in the interval was measured and divided by 20 to obtain the resistance value per hole. The results of evaluating the conductivity of the coating film b by this resistance value are shown in the lower column of Table 2.

As is clear from this result, Examples 1 to 1
In No. 9, the specific compounding materials used in the present invention are properly combined and high conductivity is obtained. This high conductivity, together with the high conductivity of the coating film b (conductive coating material) itself, allows the coating material b to smoothly flow into the through hole 33.
Indicates that it has flowed in and that a sufficient coating (coating) effect can be obtained even in dip coating.

On the other hand, in Comparative Example 1, since the amount of polyvinyl butyral is too large, the conductivity is not good. Further, in Comparative Example 2, since the amount of triethanolamine is small, the conductivity is remarkably lowered. Comparative Example 3 does not have aminophenol, and Comparative Example 4 has too much resol-type phenol resin, and thus has poor conductivity. In Comparative Example 5, the conductivity was low in the resol-type phenol resin, and a coating film capable of measuring the conductivity could not be formed.

Further, Example 10 shown in Table 3 in which no thixotropic modifier (polyvinyl butyral resin) was added
-17 and Comparative Examples 6-9 were prepared, and the resistance values were measured in the same manner as described above. The results are shown in the lower column of the table.

[0038]

[Table 3]

From this, it can be understood that Examples 10 to 17 are excellent in conductivity. Comparative Example 9 has a problem in forming a coating film.

In Examples 1 to 9, the thixotropic adjusting agent was added, so that Examples 10 to 10 were not added.
Compared with No. 17, there is an advantage that no sagging occurs after dip coating. Moreover, each Example 1-5, 10-14.
Is a resol type phenolic resin (I) in Table 1,
When the content of the resin satisfies the requirement of claim 3 and the resin has the same content, higher conductivity is obtained compared to other resins (see Example 2 and Examples 7 to 9 and Example 10 and Examples 15 to 17). ).

[0041]

Since the present invention is constructed as described above,
A hybrid IC with a shield layer having excellent conductivity can be obtained by dip coating. Further, the workability is good, and the manufacturing cost can be reduced.

[Brief description of drawings]

1 is a front view of one embodiment, and b is a sectional view taken along line XX of FIG.

FIG. 2 is a sectional view of a resistance test piece.

FIG. 3A is a plan view of the same test piece, and b is a schematic view of the same back surface.

[Explanation of symbols]

 1 substrate 2 chip component 3 resistor 4 lead terminal 4a ground lead terminal 5 protective layer 6 shield layer

Claims (4)

(57) [Claims] 1. An electronic component element is mounted on a substrate, the insulating layer is covered with a protective layer, and a required number of lead terminals are projected from the protective layer. ) To (D), a shield layer of conductive paint is formed, and the shield layer is electrically connected only to the ground lead terminal of the lead terminals. Note (A) 100 parts by weight of metallic copper powder surface-coated with 0.05 to 0.2 parts by weight of titanate, zirconate, or a mixture thereof (B) 5 to 33 parts by weight of resol type phenol resin (C) amino compound 0 0.5 to 3.5 parts by weight (D) Chelate layer forming agent 3.0 to 10 parts by weight 2. The hybrid IC according to claim 1, wherein the conductive coating material is a mixture of the following (A) to (E). Note (A) 100 parts by weight of metallic copper powder surface-coated with 0.05 to 0.2 parts by weight of titanate, zirconate, or a mixture thereof (B) 5 to 30 parts by weight of resol type phenolic resin (C) thixotropic adjustment Material 0.5 to 4 parts by weight (D) Amino compound 0.5 to 3.5 parts by weight (E) Chelate layer forming material 3.0 to 10 parts by weight 3. The hybrid IC according to claim 1 or 2, wherein the resol type phenolic resin is as follows. The 2-1 substitution product, 2,4-2 substitution product, 2,4,6-3 substitution product, methylol group, dimethylene ether, each infrared transmittance of phenyl group is 1, m, n, a, b, When c,
Between each transmittance, (a) l / n = 0.8 to 1.2 (b) m / n = 0.8 to 1.2 (c) b / a = 0.8 to 1.2 ( D) A resole type phenolic resin in which the relationship of c / a = 1.2 to 1.5 is established. 4. When manufacturing the hybrid IC according to any one of claims 1, 2 and 3, a protective layer and a shield layer of the hybrid IC are used as a substrate on which an electronic component element is mounted, an insulating resin bath or a conductive paint. A method for producing a hybrid IC, which is characterized in that the hybrid IC is formed by dip coating which is immersed in a bath.